This invention relates generally to electrical and/or optical cables. More specifically, the present invention relates to active optical cables, particularly for use in aerospace, military, and/or industrial applications in harsh environments.
Most interconnects in harsh environments, particularly for aerospace, military, and/or industrial applications, may be implemented using electrical cables. Using electrical cables may have significant advantages, including: the ability to use ruggedized, blind-mateable electrical connectors such as the 38999; flexibility in integrating different types of data; the ability to distribute electrical power; and/or the ability to operate in harsh environments including those with extended temperature ranges and/or high levels of contamination. However, the use of electrical cables for these interconnects also may have disadvantages, including: susceptibility to electromagnetic interference; large cable size and/or weight; and/or limited ability to upgrade to higher bandwidths and/or longer transmission distances.
In principle, optical data transmission may address these disadvantages. However, existing optical interconnect solutions have fallen drastically short of providing a viable solution for interconnects in these applications and/or environments. The vast majority of optical interconnects may be implemented to enable high bandwidth data transmission over relatively large distances that may be difficult and/or impossible to achieve with electrical interconnects. Although the protocols used may vary, the electrical format of the data may typically be a differential signal input such as a low-voltage differential signal (LVDS) or current mode logic (CML). An example of this type of optical interconnect is the QSFP active optical cable (see http://rhu004.sma-promail.com/SQLImages/kelmscott/Molex/PDF_Images/987650-5361.pdf).
The QSFP active optical cable may be a board edge pluggable product that provides four optical channels with bandwidths up to 10 Gbps, primarily for commercial datacom applications. However, the QSFP active optical cable may have a number of drawbacks and/or limitations. For example, the QSFP active optical cable only works with differential signal inputs. Further, the QSFP active optical cable does not enable electrical power distribution. Also, the electrical connection and/or package used in the QSFP active optical cable may not be ruggedized for harsh environments.
A small number of other data types have been implemented using optical interconnects such as digital visual interface (DVI) (see http://www.dvigear.com/fiopca.html) and/or 10/100 Base-TX Ethernet (see http://protokraft.com/products/media-converters/d38999-33vdc.html). However, no solutions exist for the integration of multiple data types with a variety of different electrical formats and/or bandwidths. In addition, none of these products enable the distribution of electrical power with a flexible voltage and/or current. Further, none of these products may operate over a wide range of noisy supply voltages. While products such as the DVI active optical cable integrate the electronics and/or optoelectronics into the DVI connector and/or eliminate optical connectors in the interconnect, these products may not be ruggedized for harsh environments and/or lack significant health monitoring capabilities. Products such as the 10/100 Base-TX Ethernet optical module may be integrated into a ruggedized connector, but fail to provide a ruggedized, blind-mateable electrical connector. Further, the 10/100 Base-TX Ethernet uses an optical connection in the ruggedized connector that severely limits its suitability to harsh environments and/or makes field maintenance very difficult, if not impossible. In addition, the DVI active optical cable and/or the 10/100 Base-TX Ethernet, as well as other similar related products have no health monitoring and/or built-in test capabilities.
Although optical interconnects may be incorporated in limited situations in applications such as aerospace, military, and/or industrial markets, these applications tend to be for high-bandwidth interconnects in relatively controlled environments free from significant levels of contamination and not requiring field maintenance. While a much larger section of the interconnect market in these applications could greatly benefit from some of the inherent advantages of optical interconnects, they require solutions that may be drastically different from existing products in both form and/or function.